Firearm



H. WESSON Feb. 18, .1941.

FIREARM 2 Sheets-Sheet 1 Filed June 28, 1939 H. WESSON Feb. 1 8, 1941.

FIREARM 2 sheets-sheet Filed June 28, 1939 A WM @M %\k m/N/mw Kme Numan@ @d Patented Feb. 18, 1941 PATENT OFFICE FnmAnM` f,

Harold Wesson, Springeld, Mass., assignor to Smith and Wesson, Inc., Springfield, Mass., a, corporation of Massachusetts Application Jane 28, 1939, Serial No. 281,565

12 Claims.

This invention relates to firearms of the automatic type and more particularly to low-power firearms in which the bolt recoil is resisted only by the recoil spring and the inertia of the mov- 5 ing parts.

Objects of the invention are to provide a firearm which is simple and economical to construct.

which can be assembled and disassembled quick- 1y and easily, which is durable and reliablein use, which may be loaded with facility, which feeds cartridges to the tiring chamber smoothly and safely, which extracts the empty cases uniformly and reliably, which ejects the empty cases positively and safely, and which is generally superior to rearms of the aforesaidv type.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which Fig. 1 is a side elevation with a part broken 20 away;

Fig. 2 is a top plan;

Fig. 3 is a section on line 3--3 of Fig. 1; Fig. 4 is a section on line 4--4 of Fig. 1; Fig. 5 is a section on line 5-5 of Fig. 1;

25 Fig. 6 is an enlarged side elevation showing parts in section and parts broken away and a modied fore-grip.

Fig. '7 is a, similar view showing vthe parts in the position which they occupy at the moment 30 of ejection;

Fig. 8 is a section on line 8-8 of Fig. '1;

Fig. 9 is a bottom plan of the front end of the bolt with parts broken away; and

Fig. 10 is a bottom plan of the modified foregrip shown in Fig. 6.

The particular embodiment of the invention chosen for the purpose of illustration comprises a submachine gun having a cylindrical receiver I, a frame 2 fitting over the rearward end of the receiver, a stock 3 fast to the frame 2, a barrel 4, a combined fore-grip and magazine holder 5 containing a magazine 6, and a sight 1. The receiver is provided with a slot 10 to accommodate the boltactuator 80. The fire-control mechanism comprises a sear 8 carried by the bolt (Fig. 6), a trigger 9, a safety IIJ movable between the safe position shown in full lines in Fig. 6 to the inoperative `position 50 shown in broken lines in the same 'figura and a controller Il for changing from semi-automatic to full-automatic operation. This fire-control mechanism forms the subject matter of an application, by Edward S. Pomeroy, Serial No. 55 281,557 led on even date herewith, and further description is unnecessary for the purpose of K the present disclosure.

The fore-grip 5 comprises a box-like member I2 which is open at the front to receive the magazine 6, a cap I3 which'closes the forward 5 portion of the bottom of the container, a catch I4 for retaining the magazine in the holder and a t'op portion I5 having inturned lips I6 which slide into grooves in the receiver from the front of the receiver. The sight 1 also has inturned 10 lips which slide into grooves in the receiver from the front of the receiver. The forward end of the receiver is recessed to receive the rearward end of the barrel, and the end of the barrel has an external flange I1 which provides a forwardly l5 facing shoulder. Threaded into the recess in the receiver is alnut I8 which seats against the barrel shoulder to retain the barrel in thereceiver. The nut I8 also overlaps the lips -II of the magazine holder and the lips of the sight 1 20 to retain these parts in position as well as the barrel. A key I9 is pinned in a slot in the bottom of the receiver to extend into' a slot in the iange I1 of the barrel thereby to hold the barrel in fixed angular relationship with respect to the receiver. This construction is described and claimed in the copending application of Edward S. Pomeroy, Serial No. 281,558 filed on even date herewith, and further description is unnecessary for the purpose of the present application.

According to the present invention the ring chamber 2l is not located in the usual position at the extreme rearward end of the barrel but is Aseparated from the real` end of the barrel by a 35 throat portion 22 whose diameter approximates the maximum diameter of the cartridge case. The length of the throat 22 is at least approximatelyequal to the maximum diameter of the cartridge and it is preferably considerably longer.

As shown in Figs. 6 and '7 the ring chamber is vslightly tapered and is provided at its forward end with a shoulder 23 against which the cartridge case seats.

4As shown in Fig. 8 the receiver is cylindrical 45 and is provided with a cylindrical bore. The forward end 24 of the bore has approximately the same radius of curvature as that of the throat 22 and the rearward end of the bore 25 has a larger diameter. The bolt comprises a cylindrical rearward portion 26 tting the rearward portion of the, receiver and a smaller cylindrical portion 21 fitting the forward portion of the'receiver and, when the bolt, is in forward position. also extending into and lling the throat 22 (Fig. 6). The rearward end of the bolt is recessed to receive the recoil spring 29. The firing pin 36 is normally held in retracted position by the spring 3| and moves forwardly into firing position against the action of the spring in response to its own inertia when the larger rearward portion 26 of the bolt seats against the shoulder 33 in the receiver. The forward end of the laigr portion 26 of the bolt is provided in its upper side with a slot 34 to receive the ejector stop 35 which is held in position by the screw 36 and which has a nose 3.1 projecting into the path of an ejector 38 mounted in a recess in the upper forward end of the bolt. The ejector is held in the recess in the bolt by means of a pin 39 extending through a slot in the ejector, a spring 49 being interposed between the pin and the rear end of the ejector yieldingly to hold the ejector in the retracted position shown in Fig. 6. The rear end of the ejector projects upwardly into a groove 40 in the top of the receiver. As the bolt arrives at the fully retracted position shown in Fig. 7 the upwardly projecting portion of the ejector engages the nose of the stop 35 thereby ejecting the cartridge case downwardly through the fore-grip and thence through an opening 90 in the bottom cap I3 (Fig. 1).

The cylindrical forward portion 21 of the bolt is provided with a rib 50 along its lower side, the rear end of the barrel being provided with a corresponding groove 5I. At its forward end the rib 50 is provided with a longitudinal undercut groove 55 in which is mounted the extractor 4| and a follower 53. The extractor is pivotally mounted on a pin 54 and the follower 53 has a anged head 51 fitting in the undercut groove to retain it in the groove. The follower is pressed forwardly by spring 56, the forward end of the follower being inclined to press the extractor in a counterclockwise direction about the pivot pin 54.

The modied fore-grip shown in Figs. 6 and 10 includes a cover 95 for the opening 90 in the bottom I3 of the fore-grip, the cover being hinged to the bottom at 96 and held in closed position by the spring 91. With this construction the empty cartridge cases accumulate in the rear chamber 98 of the fore-grip until the cover 95 is depressed to dump the contents.

From the foregoing description and the accompanying drawings, particularly Figs. 4 and 7, it will be evident that the inner surface of the receiver facing the magazine 6 has the same radius of curvature as the throat of the barrel and is coaxial therewith. Thus the upper side of the receiver is flush with the throat of the barrel so that cartridge cases may slide smoothly into and out of the barrel. As fresh cartridges are pushed into the barrel they are pressed upwardly against the top of the receiver by the succeeding cartridges in the magazine and when the empty cartridge cases are withdrawn from the barrel they are held against the top of the receiver by the extractor. Thus an empty cartridge case does not change position in relation to the bolt during its entire movement from the firing chamber back to the ejector stop.

By advancing the ring chamber and causing the bolt to project into the barrel the recoil of the bolt need be retarded only by the recoil spring and the inertia of the moving parts, because the projectile leaves the forward end of the barrel before the bolt leaves the rearward end of the barrel. Thus the breech pressure drops to a low value before the cartridge case is withdrawn from the barrel. and it is unnecessary to provide a positive lock to hold the bolt in closed position during the initial period of high breechpressure.

Another characteristic feature of the firearm consists in that all of the principal parts are circular in cross-section and can therefore be machined economically on ordinary turning machines.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A firearm comprising a barrel having an advanced firing chamber with a throat between the chamber and the rear end ofthe barrel, the diameter of the throat approximating the maximum diameter of the cartridge case, a bolt the forward end of which extends into said throat when the bolt is in firing position, the diameter of said bolt end approximating that of said throat, a receiver having a bolt bore and a cartridge opening through which cartridges may be fed to said bore and thence to said chamber, the side of `said bore 2 opposite said opening being closed and having a radius of curvature approximating that of said throat and being approximately coaxial with the throat, and means for ejecting empty cartridge cases from a side of said bore other than said side.

' 2. A rearm comprising a barrel having an advanced ring chamber with a throat between the chamber andthe rear end of the barrel, the diameter of the throat approximating the maximum 3 diameter of the cartridge case, a bolt having a nose which extends into said throat when the bolt is in ring position, the diameter of said nose approximating that of said throat and the length of said nose and throat being so correlated with the inertia of the bolt that the projectile leaves the forward end of the barrel before said nose leaves said throat, a receiver having a bolt bore and a cartridge opening through which cartridges may be fed to said bore and thence to said chamber, the side of said bore opposite said opening being closed and having a radius of curvature approximating that of said throat and being approximately coaxial with the throat, and means for ejecting empty cartridge cases from a side of said bore other than said side.

3. A rea'rm comprising a cylindrical receiver having a cylindrical bore, a cylindrical barrel having its bore coaxial with said bore and having an advanced firing chamber with a throat between the chamber and the rear end of the barrel, the receiver bore comprising forward and rearward portions, the diameter of the forward portion approximating that of said throat and the diameter of the rearward portion being greater, a cylindrical bolt having a rearward'portion fitting the rearward portion of the receiver and a forward portion tting said forward portion of the receiver and said throat, 'the forward portion of the bolt being long enough to extend into said throat to the advanced firing chamber when the bolt is closed, thereceiver having an opening in its lower side, a hollow fore-grip mounted over saidV opening, means for feeding cartridges upwardly in the forward portion of the fore-grip and an ejector mounted in the upper part of the receiver to eject empty cartridge cases downwardly through the rearward portion of said foregrip.

4, A firearm comprising a receiver having a 75 cylindrical bore. a cylindrical barrel having its bore coaxial with said bore and having an advanced firing chamber with a throat between the chamber and the rear end of the barrel, a cylindrical bolt having a portion tting said cylindrical portion of the receiver and said throat, the bolt being long enough to extend into said throat to the advanced firing chamber when the bolt is closed, the receiver having an opening in its lower side, a hollow fore-grip mounted over said opening, means for feeding cartridges upwardly in the forward portion of the fore-grip and an ejector mounted in the upper part of the receiver to eject empty cartridge cases downwardly through the rearward portion of said fore-grip.

5. A firearm comprising a receiver having an elongate opening in its lower side, a hollow foregrip mounted over said opening, means for feeding cartridges upwardly in the forward portion of the fore-grip and an ejector mounted in the upper part .of the receiver to eject empty cases downwardly through the rearward portion of said fore- 6. A iirearm comprising a receiver having an opening in its lower side, a hollow fore-grip mounted over said opening, said fore-grip projecting downwardly from the receiver and having such restricted horizontal dimensions that its iront and rear surfaces may be grasped simultaneously with one hand, and an ejector arranged in the upper part of the receiver to eject empty cases downwardly through the hollow fore-grip.

7. A rearm comprising a receiver having an elongate opening in one side, means for feeding cartridges into the receiver through the forward end of said opening, and an ejector mounted in the receiver to eject empty cases through the rear end of the opening. v

8. A iirearm comprising a receiver having an elongate opening in one side, means for feeding cartridges-into the receiver through the forward end of said opening, an ejector arranged to eject empty cases through the rear end of the opening, and means detachablymounted on the receiver to catch the ejected cases.

9. Av rearm comprising a receiver having an opening in its lower side, a fore-grip 'mounted under the receiver, the fore-grip having a chamf ber presented to said opening, and means to eject empty cases through said opening into said chamber, said fore-grip projecting downwardly from the receiver and having such restricted horizontal dimensions that its iront and rear surfaces may be grasped simultaneously with one hand.

`when the bolt is in firing position, the diameter of said bolt end approximating that of said throat, a receiver having a bolt bore and a cartridge opening through which cartridges may be fed to said bore and thence to said chamber, the side of said bore opposite said opening being closed and having a radius of curvature approximating that of said throat and being approximately coaxial with the throat, and means for ejecting empty cases through said opening.

11. A firearm comprising a barrel having an advanced ring chamber with a throat between the chamber and the rear end of the barrel, the diameter of the throat approximating the maximum diameter of the cartridge case, a bolt the forward end of which extends into said throat when the bolt is in ring position, the diameter of said bolt end approximating that of said throat, a receiver having a bolt bore and an elongate opening through which cartridges may be fed to said bore and thence to said chamber, the side of said bore opposite said opening being closed and having a radius of curvature approximating that of said throat and being approximately coaxial with the throat, means for feeding cartridges through one end of said elongate opening and thence against said side of the bore, and means for ejecting empty cases through the other end of said opening.

12. A firearm comprising a barrel having an advanced firing chamber with a throat between the chamber and the rear end of the barrel, the diameter of the throat approximating the maximum diameter of the cartridge case, a bolt the forward end of which extends into said throat when the bolt is in firing position, the diameter of said bolt end approximating that of said throat, a receiver having a bolt bore and a cartridge opening through which cartridges may be fed to said bore and thence to said chamber, the side of said bore opposite said opening being closed and having a radius of curvature approximating that of said throat and being approximately coaxial with the throat, yand means for ejecting cartridges from that side of the receiver containing said opening.

HAROLD WESSON. 

